The present invention relates generally to miter rail track joints and, more particularly, to miter rail track joints between stationary and vertically movable track sections for use on bridges.
Railroad bridges are commonly used to span waterways used by commercial, military and pleasure vessels having equipment or super structures extending a sufficient height above the elevation of the railroad bridge deck such as to make passage impossible unless the deck is moved out of the vessel""s path. In light of this, there are different kinds of railroad bridges that have movable decks to permit uninterrupted passage of such vessels or boats as necessary. The bridge decks are designed to be in an operating position that enables the passage of rolling stock wheels over the bridge and an inoperative position in which the deck is moved in relation to the stationary approach track section in order to permit the vessel or boat to move through the bridge as a result of physically displacing the movable deck out of the vessel path. The most common types of movable railroad bridge decks are the swing bridge, the vertical lift bridge and the bascule bridge. The present invention has applicability to all of these different bridge types. However, for purposes of this description, the invention will be described with reference to a swing bridge only.
A swing bridge has a deck that is generally supported on a turntable that rotates approximately 90xc2x0 about a vertical axis of rotation and in a substantially horizontal plane between the train passage and vessel or boat passage positions. A vertical lift bridge has a pair of towers on opposite ends of the bridge deck. Machinery is used to raise and lower the deck while maintaining the deck in a substantially horizontal orientation. Finally, a bascule bridge has a bridge deck that is pivotally connected to a bridge approach, pier, etc., about a horizontal pivot axis that enables the deck to swing upwardly and downwardly.
Miter rails are commonly used as transition points to bridge the gap between adjacent ends of a section of vertically movable track (commonly referred to as xe2x80x9clift railsxe2x80x9d) and a section of stationary track (commonly known as xe2x80x9capproach railsxe2x80x9d). In prior art FIG. 1, by way of example, there is disclosed a miter rail joint 10 located between a stationary track section 12 (approach track) and a movable track section 14 (e.g. located on a swing span of a swing bridge). In this conventional system, the approach left and right-handed rails 12a and 12b are made of conventional rolling stock steel rail (these are fixed running rails) that are conventionally fastened to rail ties (not shown) using appropriate rail plates 16 and rail clips all supported by a fixed structure 18 such as a stationary structure in the form of a roadway, bridge pier, or other fixed railway support structure. The movable rail section 14 are left and right lift rails 14a,14b that are also formed from conventional rolling stock fastened with rail plates, rail ties, rail clips, etc., to a movable structure 20 that may be a deck of a vertical lift bridge or a bascule bridge, or a turntable of a swing bridge.
In the conventional design, the miter rail joint 10 is formed from a pair of solid manganese rails 12a,14a and 12b,14b that are respectively spot welded to joining ends of the conventional steel rail stock 22 at points 24 remote from the miter rail joint. These solid manganese rails 12a,14a and 12b,14b have a rectangular cross-section as best depicted in FIG. 3 and the facing ends of the respective approach and lift manganese rails 12a are respectively notched at 26 and 28 and milled (as shown in FIGS. 2 and 4) so that the upper longitudinally extending parallel edges 30a and 30b along the field and gage sides of the respective fixed and lift rails are in respective alignment with each other to provide a smooth travel surface across the miter joint 10 for rolling wheel stock.
The use of manganese rails 12a,12b and 14a,14b requires that the remote ends of the fixed and lift manganese rail sections be butt welded (e.g. at 24) to ensure proper connection to the steel rail stock 22.
Other types of miter rail systems for use in bridge crossings are known in which, for example, a separate rider rail is bolted to the outer side of a stationary running rail of the miter rail system that supposedly minimizes chipping damages that are believed to be caused by the upper end edges or corners of rider rails of other miter rail systems as known in the prior art. However, the use of such rider rails necessitates additional components in the area of the miter rail joint which in turn necessitates the assembly and installation of additional rail items that must be both maintained and repaired.
A need, therefore, exists for a miter rail system of a simplified design that is capable of reliable use in rugged environments.
A miter rail system, in accordance with the present invention, comprises a fixed running rail and a lift running rail each made of a thick web material having a crown or head, a base, and a web extending between the base and crown. Each running rail and fixed rail has facing ends that are each milled out to form a notch extending through the associated crown and base that enable the fixed and running rail ends to interfit with each other along the extent of the notches so at least gage sides of the respective rails are in alignment with each other to provide a generally smooth and uninterrupted surface for rolling stock wheels.
By forming the web from a thick web material, typically in the range of 1xc2xc-1xc2xe inch, whereas conventional web thicknesses of rail steel stock are about xc2xe inch, a sufficient amount of web material remains at the joint, coextensive with the notch, to support the remaining portions of the crown supporting the rolling stock wheels during use.
Preferably, the ends of the rails that ultimately oppose each other to form the miter rail joint are formed by bending one end of the associated rail over a predetermined length and then milling the notch in the bent end to form the notch along an inward facing surface that is preferably coextensive with a side of the web facing the notch. The opposite side of the crown and face are also milled to remove the bent portion and enable the side of the crown facing away from the notch to be coextensive with unbent rail portions immediately adjacent thereto.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein only the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive.